What has the author S L Th J van Agt written?

There is no author named "S L Th J van Agt." There are several people with the name "Van Agt" who have written books, but none with the initials "S L Th J."

It is possible you are thinking of Ruud Lubbers, who served as the Prime Minister of the Netherlands between 1982 and 1994. He has written several books on political economy and international relations.

Could you please provide more context about the author you are searching for?